Three massive BESS projects have been launched in Europe: BW ESS has broken ground on a 1GW/5.7GWh system in Germany, while Greenvolt and Giga Storage have enlisted suppliers (BYD and Tesla) for 2.4GWh and 2.8GWh projects in Poland and Belgium.
BW ESS breaks ground on one of Europe’s largest BESS
Battery energy storage system (BESS) owner-operator BW ESS has broken ground on a 1GW/5.7GWh BESS in Germany, among the largest in Europe.
The Klostermansfeld project is in Mansfeld-Südharz region, Saxony-Anhalt, in close proximity to the Klostermansfeld substation, and is the largest of its kind in Germany, BW ESS said.
BW ESS took ownership from developer Zelos (with whom it partnered last year) earlier this year, though Zelos will continue to provide targeted support on local site matters until the project is ‘further into construction’, at the end of 2026.
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BW ESS is target commercial operation for the project in 2028, a spokesperson told Energy-Storage.news. They also said that the supplier will be ‘announced in due course’, while we also asked them about its route-to-market (RTM) strategy for such a large project.
“Our revenue strategy for this project is currently under review. We’ve pursued a variety of approaches across our portfolio, determined on an asset-by-asset basis,” they said, perhaps indicating the project is very early-stage construction.
BW ESS typically funds its projects from its own balance sheet initially during construction, before securing offtake and any external financing once it is underway. CEO Erik Strømsø spoke about the reasons for this (and more) in a video interview with us earlier this year (Premium access).
Roberto Jiménez, executive director at BW ESS, said: “We’ve made a long-term commitment to help realise the potential of energy storage in Germany and Klostermansfeld BESS will be our first German asset to enter construction.”
Project news in Germany has accelerated in the past several weeks since the situation with BESS and grid fees was clarified, while we’ve also published extensive analysis, interviews, a guest blog and a webinar on the major market dynamics in Germany in that time: see it all here.
Jiménez recently said that investors in the German market were starting to price BESS projects beyond 2029, despite energy storage’s grid fee exemption expiring in August that year.
Greenvolt enlists BYD for another Poland BESS
IPP Greenvolt Power has continued to collaborate with EV and BESS firm BYD with a supply deal for another Poland project, the 600MW/2.4GWh Siedlce.
It said the project will be the largest BESS in Poland, and it follows the supply agreement for two smaller projects in the country totalling 1.6GWh announced last year.
Like most large-scale BESS projects in Poland it has secure long-term revenues through the capacity market (CM), the bedrock of the business case for large-scale storage there. Around 5GW of contracts have been given to BESS over four annual auctions in 2022-2025, though the figure fell for the first time in 2025. Because of the de-rating factor in the CM, the total size of projects coming online with CM contracts is much higher at 15-20GW.
Construction on the Siedlce project is to start in Q3 2026 while commercial operations are expected in 2027.
BYD will supply its Haohan BESS solution, its ultra high energy density product launched in September 2025. Haohan appeared to push what could be packed into 20-feet containers to its limit, at 10MWh.
We interviewed Greenvolt’s head of storage last year about the company’s approach to its BESS projects and supplier selection, read it here (ESN Premium access).
Giga Storage signs LOI with Tesla for 2.8GWh Netherlands BESS
BESS platform Giga Storage has signed a letter of intent (LOI) for the construction of its 2.8GWh Green Turtle project in Belgium.
The project will be one of the largest in Europe and a ‘crucial link in the European energy transition’, Giga said. The LOI was signed at the Smarter E Europe trade show and conference last week.
Under the agreement, both parties have agreed to negotiate exclusively on the full delivery of the project, with Tesla expected to take on the full EPC scope and provide its Megablock technology (launched around the same time as BYD’s Haohan).
The final contracts are expected to be signed this summer when project financing will be finalised.
“We are excited to collaborate with GIGA Storage on the execution of this project. Providing support across construction, hardware, software, and long-term service allows us to accelerate timelines, reduce project risk and ensure performance throughout the product lifetime,” said Mike Snyder, VP Tesla energy & charging.
The Green Turtle project is located on the Rotem industrial estate in Dilsen-Stokkem, in the Belgian province of Limburg, and benefits from a 380kV connection to the Belgian grid. Giga Storage initially told us back at the start of 2024 that the project would start construction that year. Had it done so, Giga would not have benefitted from the big price falls seen in the industry in the past few years. The company is also deploying BESS in the Netherlands and Germany.
